A discussion of uncertainty in measurement is always appropriate. A discussion and summary of this type of analysis can be found in the appendix of your text, pages A11 through A14. In this discussion, standard deviation is mentioned on page A12.

1. First you need to enter your data into a list. To do this do the following:

a. Press "2^nd" (the yellow key in the upper left hand corner of key pad)

b. Press "(" (a curly brace should appear)

c. Enter your first number (try 2.75 followed by the comma key)

d. Enter the next number (try 2.82 followed by the comma key)

e. Enter a 3^rd number (try 2.76)

f. Press the "2^nd" key followed by the ")" key. A closing curly brace should appear.

g. Press the "STOà " key.

h. Press the "2^nd" key followed by the "1". An "L1" should appear.

i. Press the "ENTER" key. Your data is stored in a list.

2. To compute the mean (average) of the list values do the following:

a. Press the "2^nd" key followed by the "STAT" key. A menu should appear with the labels "NAMES", "OPS", and "MATH" across the top.

b. Highlight the "MATH" using the cursor keys (the 4 4 arrow keys in the left corner).

c. Press the "3" key and "mean(" should appear.

d. Press the "2^nd" key followed by the "1". An "L1" should appear.

e. Close the parentheses using the ")" key.

f. Press the "ENTER" key. The mean "2.7766666667" should appear.

3. To compute the standard deviation of the list values do the following:

a. Press the "2^nd" key followed by the "STAT" key. A menu should appear with the labels "NAMES", "OPS", and "MATH" across the top.

b. Highlight the "MATH" using the cursor keys (the 4 4 arrow keys in the left corner).

c. Press the "7" key and "stdDev(" should appear.

d. Press the "2^nd" key followed by the "1". An "L1" should appear.

e. Close the parentheses using the ")" key.

f. Press the "ENTER" key. The standard deviation ".037859389" should appear.

4. To clear the list to start over, do the following:

a. Press the "2^nd" key followed by the "+" key. A menu should appear with the label "MEMORY" across the top.

b. Press "4". The lists are now clear and you can start over.

1. Open an Excel spread sheet.

2. Enter your data in cells, e.g. enter "2.75" in cell "A1", "2.82" on cell "A2" and "2.76" in cell "A3".

3. To find the mean, place the cursor in cell A4 and click on the sigma symbol (the Greek "S" on the button bar.

4. To find the standard deviation do the following:

a. Place the cursor in cell "A5".

b. From the menu bar select "Insert" and select "Function".

c. A menu window will appear.

d. Select the category "Statistical"/

e. Scroll down the list of functions until you get "STDEV". Press enter or click on this item.

f. In the next window that comes up, correct the range of cells to be "A1:A3".

g. Click on the "OK" button. The standard deviation should appear.